L/Battery - go large or go lithium?

[Chris1983]

Hello all,

I am working up courage to swap split charge relay with a Victron DC to DC and Ablemail 12-2.

I only currently have a 75 sized leisure battery. So was thinking of changing that too for a bigger capacity.

This is all under driver seat (impacted by diesel heater dusting).

I have 200w Solar, my question is, should I replace with a larger lead battery, or can I do lifepo (do not at this point have skill or resources to swap out all EHU which I believe maybe needed.

Any thoughts welcome?

Battery runs small dometic fridge, 12v electrics and heater. No inverter if this makes any diff

 

[Chris1983]

Thread retitled from ‘Battery Question’.
Ads_Essex 30/08/24 1905hrs

Just a bump

 

[TallPaul_S]

Both!

Tbh even a 100Ah LiFePO4 and DC-DC will be a massive upgrade, you've currently got 22.5Ah of usable capacity with 75Ah and a 50%-80% usable state of charge. Keeping a LiFePO4 above 20% gives 80Ah usable.

You'll need 25-30Ah to run a fridge for 24hrs, so that 100Ah LiFePO4 gives you 3 full days before any solar has been added.

If your usage is light with no big inverter etc then 100Ah and 200w solar should be fine. It's only when you want multiple days off grid with little to no solar, and induction cooking/coffee makers etc that you need to step up to 200Ah+.

 

[Chris1983]

Thanks for reply, would I need to do anything with EHU?

Cos for that, I’d be well out if depth

 

[TallPaul_S]

Thanks for reply, would I need to do anything with EHU?

Cos for that, I’d be well out if depth

If you've already got EHU then you just need to make sure the 240v charger is lithium compatible.

Although, with LiFePO4 and a decent bit of solar, you may not need EHU any more.

 

[Chris1983]

If you've already got EHU then you just need to make sure the 240v charger is lithium compatible.

Although, with LiFePO4 and a decent bit of solar, you may not need EHU any more.

How do I work that out? This is all quite exciting!

Not sure also on space, I have heater ducting under driver seat currently with 75 battery. And going to try and fit Victron and Ablemail in there too

 

[ginkster]

I’d definitely recommend going lifepo4 and looking at a 100ah size, which will be approximately the physical size of your existing battery. Does what you have already work for you or are you short of power? What’s your typical usage?

I find my 105ah Fogstar Drift is essentially self sustaining with a 200w solar power, even on overcast/rainy days. I’m not a heavy user (no inverter) and only need fridge, lights, usb chargers and diesel heater etc. The battery remains well above 90% by morning and is full again by lunch even on the gloomiest day. I don’t really need the DC-DC and haven’t bothered installing the mains charger yet as I don’t use EHU now (makes it refreshingly flexible when finding sites!).

You will struggle to get all 3 components under a single seat with heater pipes there too. Potentially possible if the leave lots of room and you use the new Victron 50a DC-DC as it runs cooler so doesn’t need as much space. I’d recommend putting some under your passenger seat and running the cables across (dead easy). Pic below to show my under passenger seat instal with 105ah Fogstar, Orion DC and Ablemail.

 

[Chris1983]

My usage sounds very similar to yours @ginkster .

I have double swivelling passenger seat. Would that still work?!

I bought Victron DC to DC 12/12/18 isolated I believe.

I have the Ablemail 12-2.

The split charge relay to replace is an ‘amber valley’ I was hoping I could use the wires already in place once snipped that out for everything else, but inquiries made with simply split charge have suggested full length leads to starter etc (which means trying to navigate through bulkhead which I had hoped to avoid.

Question to all if don’t mind-

-How do I know if EHU will support lifepo?

Thanks all

 

[TallPaul_S]

How do I know if EHU will support lifepo?

Hook up just provides 240v power, it doesn't directly charge the battery. For that you need a charger that runs off 240v, it's that charger that you need to check the model and check if it's got a setting on it for lithium.

 

[Chris1983]

I’ll check and post pictures for group wisdom.

Bw

Chris

 

[ginkster]

The 18a DC-DC is a little smaller and runs cooler so may fit under the drivers seat. The only way to tell is to remove the seat and lay it all out to see if they will fit. The same with the passenger seat if you need to use under there. The swivel won’t stop you but may limit the height available depending on the model of swivel (I have swivels on both seats).

I would run new cables if at all possible. The one from the starter battery is pretty easy through an existing grommet (you will be able to see it down behind the battery - probably with the existing cable through it) and under the cab floor covering. It’s easier if you take out both seats and bases and pull the floor back to access everything. That sounds difficult but is only a few bolts and takes about 20mins. You would then be free to position stuff exactly where you want it under the seats and easily run the cables (there are indents in the floor running in all directions for this).

As TallPaul says re the 240v charger.

 

[Chris1983]

 

[Chris1983]

If useful

 

[TallPaul_S]

Looks like that is only compatible with gel and lead acid, so no good for LiFePO4.

 

[Qnapper]

Hello all,

I am working up courage to swap split charge relay with a Victron DC to DC and Ablemail 12-2.

I only currently have a 75 sized leisure battery. So was thinking of changing that too for a bigger capacity.

This is all under driver seat (impacted by diesel heater dusting).

I have 200w Solar, my question is, should I replace with a larger lead battery, or can I do lifepo (do not at this point have skill or resources to swap out all EHU which I believe maybe needed.

Any thoughts welcome?

Battery runs small dometic fridge, 12v electrics and heater. No inverter if this makes any diff

We have a 180Ah LiFePO4 and 200W roof Solar with portable if needed 200watt solar (400watts/20amps on a good day) when driving we use the Victron 50amp DC to DC, which after a drive of 1 or 2 hours fully charges battery (fitted under drivers seat). buy a good LiFePO4 battery charger for campsite parking if on EHU.
We have not been on campsite EHU for over 2 years now saving around £5 each night or more.
We cook on an induction hub (have gas as a backup) boil water on electric kettle, charge phones and run Blink cameras etc etc and never run out of power. I would not swap out the EHU system, but keep it as a backup. Buy a good inverter (ours is a 1800watt and works well).
Well worth spending the extra money and I advise get the largest LiFePO4 battery that will fit under seat.

 

[Lubrown]

It’s easier if you take out both seats and bases

One tip - if you have a pop top open it up so you can lift the double seat easier. It’s not hugely heavy but heavy enough that with its size it can be awkward. With the pop top up you can stand up better and lift it.
Even more important if you have a swivel with plastic topped securing knobs to make sure you lift well clear of those - I snapped one off when trying to rush and didn’t have the top up. Kiravans were awesome and sent a new one foc! Amazing company.

 

[roadtripper]

Worth pointing out that as lead acid shouldn't really be discharged below 50% but you can easily go as low as 80% on lithium (and 90% if you have the good quality long cycle life cells) moving from 75Ah Lead Acid to 105Ah LiFePo is going to double your usable capacity in broadly the same physical space.

You'll need to change your 240v charger but that looks like a fairly straightforward swap for one of the Victron IP22 units as all the cabling appears to come to the front of the panel.

 

[Linoleum Bonypart]

EHU and inverter isn’t necessary if you usage is light … jet boil for making tea coffee

 

[roadtripper]

EHU and inverter isn’t necessary if you usage is light … jet boil for making tea coffee

Agreed, but the OP would be best advised to disconnect the existing Lead Acid EHU charger if they wanted to go that route

 

[Chris1983]

Agreed, but the OP would be best advised to disconnect the existing Lead Acid EHU charger if they wanted to go that route

What Victron unit would be swapped in for the stelling? Is that straightforward, would wiring be sufficient? I feel a little lost in it now (my issue not the excellent input on here)